The Y-axis home sensor got stuck in closed position on my N2, so the printer started printing from the wrong position and caused a damage. Not sure if this is a software or firmware change, but it would be good if a check can be put in place for all these sensors to make sure the state changes to "open" state when the head and the bed move away from home. Printing should stop if the switches do not open. The new Pro2 model might be even more susceptible to this problem because a debris can get stuck between the optical sensor. A simple checking can avoid unnecessary damage.

A nice suggestion. To achieve this, seems we need to add a second check of switches' disabled status after print starts.But what about the print starts from the origin point and moves in only one direction but the other direction keeps always at 0 value? Such as print a straight line at the most left side (X0) from Y0-Y300?

It has to be done before the print starts to avoid damage. Perhaps move to about (10,10,1) immediately after homing and before the actual print. Such a small move should be enough to open the switches and minimize damage to the mechanism in case of a problem. Check to make sure the switches have opened, then start printing. No need to re-home again, since homing was already completed.